Wafer-type valves are adapted to be clamped between opposing flanges of pipeline components. Typical wafer-type valves include butterfly valves, check valves, segmented ball valves and eccentric plug valves. A common aspect of each of these types of valves is that they are flangeless. Therefore, the pipeline components include flanges for receiving longitudinal bolts that compressedly couple the wafer-type valves therebetween. One wafer-type butterfly valve includes a generally cylindrical valve body, a valve element, a valve seat, and a retainer plate. The valve body defines an axial bore that serves as a fluid flow path. The valve body typically has a relatively small axial dimension and a radial dimension adapted to accommodate the desired pipeline application. The valve element includes a disk-shaped element pivotally supported within the axial bore of the valve body between a closed position and one or more open positions. The valve seat includes a generally cylindrical member disposed adjacent to an internal radial surface of the axial bore of the valve body. The valve seat provides a surface against which the valve element seals when in the closed position. The retainer plate includes a generally flat plate fixed to an axial end surface of the valve body to retain the valve seat within the axial bore. For optimal performance and to avoid interference between the pipeline components and the valve element, such a wafer-type valve additionally includes a centering component for centering the valve in the pipeline.
A typical centering component cooperates with the longitudinal bolts extending between the pipeline flanges to axially center the valve assembly relative to the pipeline. One known centering component includes a plurality of holes formed directly through a portion of the valve body. The plurality of holes define a fixed pattern adapted to accommodate longitudinal bolts having the same fixed pattern, thereby centering the valve body. Another known centering component includes a plurality of lugs or a circumferential flange disposed on the valve body. The lugs or flange may be formed by casting or welding or otherwise fixed to the valve body. The lugs or the flange define a plurality of holes having a fixed pattern adapted to accommodate longitudinal bolts having the same pattern to thereby axially center the valve body relative to the pipeline. A still further known centering component includes one or more clips removably fixed to the valve body. The clips each define a plurality of holes having a fixed pattern for receiving longitudinal bolts having the same fixed pattern and thereby axially centering the valve body relative to the pipeline. The clips may be replaced by a different set of clips defining a plurality of holes having a different pattern for accommodating a different pattern of longitudinal bolts.
A shortcoming of each of these known centering components includes the fact that each are adapted to accommodate only a single longitudinal bolt pattern. Bolt patterns, however, are subject to different standards or ratings for different applications and, therefore, tend to vary. For example, for any given application, the American National Standards Institute (ANSI) requires a specific flange diameter, a number of bolts, a bolt size, and a pitch circle diameter. It can therefore be appreciated that for each different application, a different bolt pattern may be required. While the clip form of the known centering components described above may be replaced by a different clip to accommodate a different bolt pattern, such replacement is time-consuming. Additionally, replacement clips adapted for use with each of the different bolt patterns must be maintained.
Another shortcoming of these known centering components is that the longitudinal bolts must be guided through the holes during installation of the valves. This requires a technician to carefully align the various components and manually guide the bolts, which can be tedious and time-consuming.
A still further shortcoming of the known centering components arises during installation of the valves within the pipelines and specifically, during the transportation and positioning of the valves. For example, technicians often require the use of a lift such as a fork lift or some other device to transport the valve assemblies. To achieve this, technicians have often hooked a cable, a strap, or some other device through one or more of the holes in the centering component. During the lifting and transporting of the valve assembly, this connection can improperly stress either or both of the centering component and the threaded fastener.